Features
OBC System Management
The Safety Processor manages the operational status of the OBC. The managed information includes system information such as:
-
Board revision
-
System version
-
Boot count
-
Uptime
-
ECC error count
This information is provided to the Main Processor.
| This feature is not implemented yet. |
OBC Status Monitoring
The Safety Processor obtains the OBC status from the sensors implemented on the OBC.
OBC Temperature Monitoring
The Safety Processor obtains temperature readings every second from multiple temperature sensors mounted on the OBC. Based on the data read from each sensor, the Safety Processor calculates and stores a valid temperature value.
When the Safety Processor receives a temperature acquisition command from the Main Processor, it sends the latest temperature data to the Main Processor.
OBC Current/Voltage Monitoring
The Safety Processor obtains current and voltage readings every second from the Current/Voltage Monitors implemented on the OBC.
Current/Voltage Monitors are implemented on the following power nodes of the OBC.
| Domain Name | Power Domain |
|---|---|
SYS domain |
Safety Processor and external supply to the OBC Module |
PS domain |
Main Processor Processor System |
PL domain |
Main Processor Programmable Logic |
Main Processor Control
The Safety Processor manages the power and reset for the Main Processor.
Main Processor Power Control
When power is applied to the OBC and the Safety Processor starts the OBC management, it powers on the Main Processor. Power is applied to all power domains of the Main Processor in accordance with the specified power-up sequence. After confirming that each power domain has reached the Power Good state, the Safety Processor releases the reset to start the Main Processor.
Main Processor Power Cycle Control
Upon request from the Main Processor, the Safety Processor performs a power cycle of the Main Processor. Power cycling is used for recovery from faults detected by the Application Processor or the Real-Time Processor, rebooting after on-orbit software updates, and restarting the system during flight software development on the ground. Power and reset controls for power cycle are performed in accordance with the sequence specified for the Main Processor device.
Main Processor Boot Control
The OBC provides a dual-bank memory configuration as the Boot Data Store for the Main Processor. Although the memory is implemented in a single memory device, it is internally divided into two independent memory banks, each with its own access interface.
Before the Main Processor starts, the Safety Processor selects the Boot Data Store. Immediately after power-on, the Boot Data Store is selected based on the boot bank information stored in the Safety Processor’s Non-Volatile Memory, and the Main Processor is started.
| This feature is not implemented yet. |
After the Main Processor has started, the Safety Processor does not switch the Boot Data Store autonomously. Switching of the Boot Data Store is performed only in response to requests from the Main Processor, such as for software updates or verification of the integrity of the stored data.
External Interfaces
The Safety Processor provides the interfaces for monitoring and controlling from external systems.
Safety Processor Telemetry/Telecommand
The Safety Processor provides the Telemetry/Telecommand interface for monitoring its status and controlling its operation and configuration. It is provided as a serial interface in SC-OBC Module V1.
Safety Processor Keep Alive Signal Output
The Safety Processor provides the Keep Alive Signal interface to indicate its status to external systems. The Safety Processor monitors its internal status, and periodically toggles the Keep Alive Signal while it confirms that it is working properly. It stops toggling the Keep Alive Signal if it defects abnormal conditions.
The Keep Alive Signal toggles at one-second intervals.